A semiconductor module can be constructed in a plastic housing composition in a manner known by the catchword “universal package.” The “universal package” has the advantage that a composite body composed of semiconductor chips and plastic housing composition is created which is characterized by a coplanar area composed of active top sides of semiconductor chips and the top side of a plastic housing composition, the edge regions and the rear sides of the respective semiconductor chips being embedded in plastic housing composition.
A “universal package” of this type has the advantage that a multilayer wiring structure can be applied on the coplanar surface in order to connect the electrodes of the semiconductor elements of the embedded semiconductor chips among one another and to external contact areas of corresponding size, on which surface-mountable external contacts can then be positioned or soldered. In the case of semiconductor power modules of this type, the problem arises that, depending on how many semiconductor chips are combined to form a semiconductor module, the number of external contact areas can rise to an arbitrary magnitude. However, the larger the number of external contacts, the more difficult it becomes to arrange the external contacts on a superordinate circuit board and to electrically connect them reliably to corresponding contact pads on the circuit board. Accordingly, there is a need to reduce the number of surface-mountable external contacts to be connected to a necessary amount.
A known semiconductor module having a first semiconductor chip comprising an active top side and an inactive rear side, the active top side being divided at least into a first connection region and into a second connection region. The semiconductor chip module furthermore has a second semiconductor chip, which has an active top side and an inactive rear side and is connected on the second connection region of the first semiconductor chip via flip-chip contacts. Finally, the semiconductor module has a substrate having a top side and an underside, the top side being provided for mounting the first connecting region of the first semiconductor chip thereon via flip-chip contacts. For this purpose, the substrate has a predetermined height that is greater than the thickness of the second semiconductor chip. Finally, the semiconductor module has a printed superordinate circuit for mounting the substrate with the aid of surface mounting.
In the case of this known semiconductor module it is possible to reduce the external connections by semiconductor chips which are arranged in edge regions of the first semiconductor chip, but the thickness of the additional semiconductor chips is so great that the height of surface-mountable external contacts in the center of the first semiconductor chip does not suffice for mounting them on a superordinate circuit board. Rather, the known semiconductor module provides for lengthening or enlarging these central surface-mountable external contacts of the first semiconductor chip by means of an intermediate substrate in such a way that the semiconductor module can be mounted on a superordinate circuit board with the aid of the intermediate substrate.
This solution has the disadvantage that a uniform solder ball size is provided both for the first semiconductor substrate, which carries additional semiconductor chips with flip-chip contacts on its underside, and for the external contacts of the first semiconductor chip. It is thus impossible for the additional substrate to be able to be dispensed with and for the external contacts situated in the center to suffice for bridging the height or thickness of the second flip-chip-mounted semiconductor devices.